The little boy ________the Snoopy doll as soon as he saw it.  [ ]

A. fell on love with  

B. felt on love with  

C. fell in love with  

D. felt in love with

物理课外小组的同学们利用天平和量筒测小石块的密度，如图所示。先用天平称出小石块的质量，天平平衡时，如图甲所示，小石块的质量为       g；再用量筒测小石块的体积，如图乙所示，其体积为      cm³。由此计算出小石块的密度为            kg/m³。